TEST ACTION APPLICABILITY
3NOTE: Inspect all air intake and turbocharger related tubes for damage,
restriction or poor connection. Any of these conditions can cause a this DTC
to set.
Turn the ignition off.
Inspect all air intake and turbocharger related tubes and connections.
were any problems found?All
Ye s!Repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Disconnect the Intake Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Intake Pressure Sensor Signal circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 5
No!Repair the Intake Pressure Sensor Signal circuit for high resis-
tance.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the Intake Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Sensor Ground circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 6
No!Repair the Intake Pressure Sensor Ground circuit for high resis-
tance.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Disconnect the Intake Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Intake Pressure Sensor 5-volt Supply circuit.
Is the resistance below 10.0 ohms?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the Intake Pressure Sensor 5 Volt Supply circuit for high
resistance.
Perform ROAD TEST VERIFICATION - VER-2.
126
DRIVEABILITY - DIESEL
P2025-INTAKE PRESSURE SENSOR PLAUSIBILITY ÐContinued
TEST ACTION APPLICABILITY
7WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
127
DRIVEABILITY - DIESEL
P2025-INTAKE PRESSURE SENSOR PLAUSIBILITY ÐContinued
TEST ACTION APPLICABILITY
6 Turn the ignition off.
NOTE: Ensure all harness connectors are connected.
Turn the ignition on.
Measure the voltage of the Intake Pressure Sensor Signal circuit by back probing
ECM harness connector.
Is the voltage above 4.85 volts?All
Ye s!Replace the Intake Pressure Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
7WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
130
DRIVEABILITY - DIESEL
P2025-INTAKE PRESSURE SENSOR SIGNAL VOLTAGE TOO HIGH Ð
Continued
Symptom List:
P2025-INTAKE PRESSURE SENSOR SIGNAL VOLTAGE TOO LOW
P2030-INTAKE PRESSURE SENSOR SIGNAL VOLTAGE TOO LOW
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2025-INTAKE PRESSURE
SENSOR SIGNAL VOLTAGE TOO LOW.
POSSIBLE CAUSES
INTERMITTENT CONDITION
INTAKE PRESSURE SENSOR 5 VOLT SUPPLY
INTAKE PRESSURE SENSOR
INTAKE PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
INTAKE PRESSURE SENSOR SIGNAL AND GROUND CIRCUITS SHORTED TOGETHER
ENGINE CONTROL MODULE
INTAKE PRESSURE SENSOR SIGNAL CIRCUIT OPEN
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
NOTE: Ensure all turbocharger inlet and outlet tubes are connected prop-
erly, without damage and restriction before continuing with this test. Also
ensure the Boost Pressure Servo Motor and Servo Motor rod are attached
and functioning properly.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Cycle the ignition key on and off several times, leaving the key on for at least 10
seconds at a time.
With the DRB, read ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 7
2 Turn the ignition off.
Disconnect the Intake Pressure Sensor harness connector.
Turn the ignition on.
Measure the voltage between ground and the Intake Pressure Sensor 5 Volt Supply
circuit.
Is the voltage above 4.8 volts?All
Ye s!Go To 3
No!Repair the Intake Pressure Sensor 5 Volt Supply circuit for an
open.
Perform ROAD TEST VERIFICATION - VER-2.
131
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
7WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
133
DRIVEABILITY - DIESEL
P2025-INTAKE PRESSURE SENSOR SIGNAL VOLTAGE TOO LOW Ð
Continued
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Test drive the vehicle.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 9
2 Turn the ignition off.
Using the Service Information wiring diagrams, inspect the wiring and connectors
between the ECM and the O2 sensor for damage, corrosion, poor terminal contact or
other problems.
Were any problems found?All
Ye s!Clean, repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
3 Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Power Supply circuit at the
O2 harness connector cavity 4.
Does the test light illuminate brightly?All
Ye s!Go To 4
No!Repair the Power Supply circuit for an open or short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Disconnect the ECM harness connectors.
Perform the following resistance measurements from the O2 harness connector to the
ECM harness connector.
O2 Sensor Cavity 1 to ECM Cavity C1-15.
O2 Sensor Cavity 2 to ECM Cavity C1-40.
O2 Sensor Cavity 3 to ECM Cavity C1-72.
O2 Sensor Cavity 5 to ECM Cavity C1-62.
O2 Sensor Cavity 6 to ECM Cavity C1-39.
Is the resistance below 10.0 ohms for each measurement?All
Ye s!Go To 5
No!Repair the circuit(s) that measured above 10.0 ohms for an open.
Perform ROAD TEST VERIFICATION - VER-2.
135
DRIVEABILITY - DIESEL
P2026-O2 SENSOR CIRCUIT FAULT ÐContinued
TEST ACTION APPLICABILITY
9WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
137
DRIVEABILITY - DIESEL
P2026-O2 SENSOR CIRCUIT FAULT ÐContinued
Symptom List:
P2034-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO HIGH
P2034-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO LOW
P2036-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO HIGH
P2036-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO LOW
P2038-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO HIGH
P2038-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO LOW
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2034-O2 SENSOR CIRCUIT
CALIBRATION VALUE TOO HIGH.
POSSIBLE CAUSES
CHECKING CIRCUIT INTEGRITY
O2 SENSOR
INTERMITTENT CONDITION
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Using the Service Information wiring diagrams, inspect the wiring and connectors
between the ECM and the O2 sensor for damage, corrosion, poor terminal contact or
other problems.
Were any problems found?All
Ye s!Clean, repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 2
2NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Test drive the vehicle.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Replace the Oxygen Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
138
DRIVEABILITY - DIESEL